Andrew McCutchen goes 2 for 3 as Pittsburgh loses 5-2

The Pittsburgh Pirates insist they're not scoreboard watching as they try to chase the franchise's first playoff berth in 21 years.

Good idea. At the moment the teams in their rearview mirror are inching closer by the day.

Jeff Locke's second-half struggles reappeared and Pittsburgh's offense again fell silent in a 5-2 loss to the San Diego Padres on Tuesday night.

The Pirates began the day tied with St. Louis for the NL Central lead but allowed Cincinnati and Washington -- both in pursuit of playoff berths -- to gain ground.

"Everybody's aware of where we are, what's going on," Pirates manager Clint Hurdle said. "At the end of the day, we had a couple of opportunities we didn't maximize on."

A night after getting one-hit by San Diego's Andrew Cashner, Pittsburgh managed just two runs against easy throwing Eric Stults (9-13).

The left-hander's fastball only tops out in the mid-80s but kept the Pirates off balance by throwing a bevy of offspeed stuff that included a pair of changeups in the mid-60s.

"He's learned how to pitch," Hurdle said. "At the end of the day we've got to continue to work hard to get the most out of our offense."

Andrew McCutchen went 2 for 3 and Marlon Byrd drove in both of Pittsburgh's runs, but the Pirates continued to have problems with the Padres.

San Diego improved to 30-10 at PNC Park since it opened in 2001 by getting to Locke.

A surprise All-Star in July, Locke again had problems with his command, allowing four runs and seven hits in five innings, striking out five and walking three. Locke is just 2-4 since mid-July.

"This ain't no different than all the other starts," Locke said. "Just falling behind early and getting behind."

Jedd Gyorko blasted a 3-run homer among his three hits and Ronny Cedeno also had three hits for San Diego.

Stults was winless in his previous 10 starts and came in with a 3-9 mark on the road. Still he never let the Pirates get comfortable, testing their patience behind a steady diet of offspeed stuff that wouldn't have broken the speed limit on most interstates.

At one point he retired Pedro Alvarez on a 66 mph changeup then dropped it down to 64 mph to get Josh Harrison to ground meekly to third. It was enough to prevent one of the National League's top-hitting teams against left-handers from cashing in.

"We had a rough game," Pittsburgh first baseman Gaby Sanchez said. "We'll try to go shower it off and win tomorrow."

Locke briefly regained his All-Star form in his last start, when he handcuffed the Chicago Cubs for seven innings to pick up his first victory in nearly two months.

The good vibes disappeared in the third, when Gyorko took an 89 mph fastball over the middle of the plate and sent it into the bleachers in left field for his 19th homer of the season.

The Pirates drew within one in the bottom of the inning thanks to a little help from San Diego right fielder Kyle Blanks, who stumbled trying to track down a sinking line drive by Byrd, allowing two runs to score.

Byrd tried to tie the game one batter later when Sanchez's infield chopper was mishandled by Gyorko at second base.

The ball trickled behind Gyorko but Cedeno -- who spent three mostly forgettable seasons in Pittsburgh from 2009-2011 -- picked it up and fired home to throw out Byrd as he attempted to score from second.

"We're struggling to score runs and he tried to plate the third one there to try and get back into it and they corralled the bobble, collect the bobble and get a throw to the plate to get it," Hurdle said.

The Pirates managed just two base runners over the final four innings, with Cedeno providing a highlight play from deep shortstop against Byrd in the eighth to provide an exclamation point as Pittsburgh stumbled again.

NOTES: Pittsburgh outfielder Starling Marte went 1 for 3 in his first start since suffering a contusion to his right index finger on Aug. 18 ... Pittsburgh C Russell Martin caught his major league-leading 29th base stealer in the ninth when he threw out Will Venable at second ... The series continues on Wednesday when Pittsburgh's Charlie Morton (7-4, 3.54 ERA) faces San Diego's Tyson Ross (3-8, 3.29 ERA).